18 feb bike ppt

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BIKE BRAKE STORE

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Page 1: 18 feb bike ppt

BIKE BRAKE STORE

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BIKEBRAKESTORE TAKES THE ART OF BRAKING VERY SERIOUSLY. BE IT ON A SPORT BIKE, ALL TERRAIN VEHICLE, SCOOTER, OR EVEN A OFF-ROAD DIRT BIKE BRAKING IS THE MOST IMPORTANT THING YOU WILL DO EVERY TIME YOU RIDE. THEREFORE WE ONLY WORK WITH THE BEST PRODUCTS AND THE TOP SUPPLIERS THAT CAN PROVIDE YOU OUR CUSTOMER WITH THE OPTIMAL STOPPING POWER. SECOND PLACE WON’T CUT IT WHEN IT COMES TO QUALITY AND SAFETY.ON THE WORLD WIDE BRAKE MARKET TODAY IT IS EASY TO FIND MANY BRAKE DISCS, BRAKE PADS IN MANY DIFFERENT STYLES AND QUALITIES. WE TAKE THE GUESS WORK OUT OF PICKING THE RIGHT COMPONENT, BECAUSE LET’S FACE IT YOU ONLY WANT THE BEST WHEN IT COUNTS.

About us…

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REGENERATIVE BRAKEBICYCLE BRAKEFIXED-GEAR BICYCLEMOUNTAIN BIKE TRAILSDOWNHILL MOUNTAIN BIKING

Types of brake

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A REGENERATIVE BRAKE IS AN ENERGY RECOVERY MECHANISM WHICH SLOWS A VEHICLE OR OBJECT DOWN BY CONVERTING ITS KINETIC ENTRY INTO ANOTHER FORM, WHICH CAN BE EITHER USED IMMEDIATELY OR STORED UNTIL NEEDED. THIS CONTRASTS WITH CONVENTIONAL BRAKING SYSTEMS, WHERE THE EXCESS KINETIC ENERGY IS CONVERTED TO HEAT BY FRICTION IN THE BRAKE LININGS AND THEREFORE WASTED.

CONTINUE………

Regenerative brake

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HISTORY

The most common form of regenerative brake involves using an electric motor as an electric generator. In electric railways the generated electricity is fed back into the supply system, whereas in battery electric and hybrid electric vehicles, the energy is stored chemically in a battery, electrically in a bank of capacitors, or mechanically in a rotating flywheel. Hydraulic hybrid vehicles use hydraulic motors and store energy in form of compressed air.

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TRADITIONAL FRICTION-BASED BRAKING IS USED IN CONJUNCTION WITH MECHANICAL REGENERATIVE BRAKING FOR THE FOLLOWING REASONS:THE REGENERATIVE BRAKING EFFECT DROPS OFF AT LOWER SPEEDS; THEREFORE THE FRICTION BRAKE IS STILL REQUIRED IN ORDER TO BRING THE VEHICLE TO A COMPLETE HALT. MOST ROAD VEHICLES WITH REGENERATIVE BRAKING ONLY HAVE POWER ON SOME WHEELS (AS IN A TWO-WHEEL DRIVE CAR) AND REGENERATIVE BRAKING POWER ONLY APPLIES TO SUCH WHEELS BECAUSE THEY ARE THE ONLY WHEELS LINKED TO THE DRIVE MOTOR, SO IN ORDER TO PROVIDE CONTROLLED BRAKING UNDER DIFFICULT CONDITIONS (SUCH AS IN WET ROADS) FRICTION BASED BRAKING IS NECESSARY ON THE OTHER WHEELS. THE AMOUNT OF ELECTRICAL ENERGY CAPABLE OF DISSIPATION IS LIMITED BY EITHER THE CAPACITY OF THE SUPPLY SYSTEM TO ABSORB THIS ENERGY OR ON THE STATE OF CHARGE OF THE BATTERY OR CAPACITORS. REGENERATIVE BRAKING CAN ONLY OCCUR IF NO OTHER ELECTRICAL COMPONENT ON THE SAME SUPPLY SYSTEM IS DRAWING POWER AND ONLY IF THE BATTERY OR CAPACITORS ARE NOT FULLY CHARGED. FOR THIS REASON, IT IS NORMAL TO ALSO INCORPORATE DYNAMIC BRAKING TO ABSORB THE EXCESS ENERGY.

Limitations

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BICYCLE BRAKE

A bicycle brake reduces the speed of a bicycle or prevents it from moving. The three main types are: rim brakes, disc brakes, and drum brakes. There have been various types of brake used throughout history, and several are still in use today

Most bicycle brake systems consist of three main components: a mechanism for the rider to apply the brakes, such as brake levers or pedals; a mechanism for transmitting that signal, such as Bowden cables, hydraulic hoses, rods, or the bicycle chain; and the brake mechanism itself, a caliper or drum, to press two or more surfaces together in order to convert, via friction, kinetic energy of the bike and rider into thermal energy to be dissipated.

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HISTORY BICYCLE BRAKE

The earliest bicycles with pedals such as the boneshaker were fitted with a spoon brake which pressed onto the rear wheel. The brake was operated by a lever or by a cord connecting to the handlebars. The rider could also slow down by resisting the pedals of the fixed wheel drive. The next development of the bicycle, the penny-farthings, were similarly braked with a spoon brake or by back pedaling. During its development from 1870 to 1878, there were various designs for brakes, most of them operating on the rear wheel. However, as the rear wheel became smaller and smaller, with more of the rider's weight over the front wheel, braking on the rear wheel became less effective. The front brake, introduced by John Kean in 1873, had been generally adopted by 1880 because of its greater stopping power.

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TYPES OF BICYCLE BRAKES

Spoon brakeDuck brakeRim brake

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SPOON BRAKESThe spoon brake, or plunger brake was probably the first type of bicycle brake and precedes the pneumatic tyre. Spoon brakes were used on penny farthings with solid rubber tyres in the 1800s and continued to be used after the introduction of the pneumatic-tyred safety bicycle. The spoon brake consists of a pad (often leather) or metal shoe (possibly rubber faced), which is pressed onto the top of the front tyre. These were almost always rod-operated by a right-hand lever. In developing countries, a foot-operated form of the spoon brake sometimes is retrofitted to old rod brake roadsters. It consists of a spring-loaded flap attached to the back of the fork crown. This is depressed against the front tyre by the rider's foot.

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DUCK BRAKE

Invented in 1897, the duck brake, aka Duck Roller Brake used a rod operated by a lever on the handlebar to pull twin friction rollers (usually made of wood or rubber) against the front tyre. Mounted on axles secured by friction washers and set at an angle to conform to the shape of the tyre, the rollers were forced against their friction washers upon contacting the tyre, thus braking the front wheel. A tension spring held the rollers away from the tyre except when braking. Braking power was enhanced by an extra-long brake lever mounted in parallel with and behind the handlebar, which provided additional leverage when braking (two hands could be used to pull the lever if necessary). Used in combination with a rear coaster brake, a cyclist of the day could stop much more quickly and with better modulation of braking effort than was possible using only a spoon brake or rear coaster brake

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RIM BRAKE

Rim brakes are so called because braking force is applied by friction pads to the rim of the rotating wheel, thus slowing it and the bicycle. Brake pads can be made of leather, rubber or cork and are mounted in metal "shoes". Rim brakes are typically actuated by the rider squeezing a lever mounted on the handleba

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BRAKE PADSThere are many designs of brake pads (brake blocks). Most consist of a replaceable rubber pad held in a metal channel (brake shoe), with a post or bolt protruding from the back to allow attachment to the brake. Some are made as one piece with the attachment directly molded in the pad for lower production costs; brake pads of the cartridge type are held in place by a metal split pin or threaded grub screw and can be replaced without moving the brake shoe from its alignment to the rim. The rubber can be softer for more braking force with less lever effort, or harder for longer life. The rubber can also contain abrasives for better braking, at the expense of rim wear. Compounds vie for better wet braking efficiency. Typically pads are relatively short, but longer varieties are also manufactured to provide more surface area for braking; these often must be curved to match the rim. A larger pad does not give more friction but wears more slowly, so a new pad can be made thinner. In general, a brake can be fitted with any of these many varieties of pads, as long as the pad mounting method is compatible. Carbon-fibre rims, as on some disc wheels, generally have to use non-abrasive cork pads.

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ROD-ACTUATED BRAKES

The rod-actuated brake, or simply rod brake, uses a series of rods and pivots, rather than Bowden cables, to transmit force applied to a hand lever to pull friction pads upwards against the inner surface, which faces the hub, of the wheel rim. They were often called stirrup brakes due to their shape. Rod brakes are used with a rim profile known as the Westwood rim, which has a slightly concave area on the braking surface and lacks the flat outer surface required by brakes that apply the pads on opposite sides of the rim.

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THE CALIPER BRAKE DESIGN

The caliper brake is a class of cable-actuated brake in which the brake mounts to a single point above the wheel, theoretically allowing the arms to auto-centre on the rim. Arms extend around the tyre and end in brake shoes that press against the rim. While some designs incorporate dual pivot points — the arms pivot on a sub-frame — the entire assembly still mounts to a single point. Caliper brakes tend to become less effective as tyres get wider, and so, deeper, reducing the brakes' mechanical advantage. Thus caliper brakes are rarely found on modern mountain bikes. But they are almost ubiquitous on road bikes, particularly the dual-pivot side-pull caliper brake.

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SIDE-PULL CALIPER BRAKESSingle-pivot side-pull caliper brakes consist of two curved arms that cross at a pivot above the wheel and hold the brake pads on opposite sides of the rim. These arms have extensions on one side, one attached to the cable, the other to the cable housing. When the brake lever is squeezed, the arms move together and the brake pads squeeze the rim.These brakes are simple and effective for relatively narrow tyres but have significant flex and resulting poor performance if the arms are made long enough to fit wide tyres. If not adjusted properly, low-quality varieties tend to rotate to one side during actuation and tend to stay there, making it difficult to evenly space brake shoes away from the rim. These brakes are now used on inexpensive bikes; before the introduction of dual-pivot caliper brakes they were used on all types of road bikes.

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CENTRE-PULL CALIPER BRAKES

Centre-pull caliper brakes have symmetrical arms and as such centre more effectively. The cable housing attaches to a fixed cable stop attached to the frame, and the inner cable bolts to a sliding piece (called a "braking delta", "braking triangle", or "yoke") or a small pulley, over which runs a straddle cable connecting the two brake arms. Tension on the cable is evenly distributed to the two arms, preventing the brake from taking a "set" to one side or the other.

These brakes were reasonably priced, and in the past filled the price niche between the cheaper and the more expensive models of side-pull brakes.

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U-BRAKESU-brakes (also known by the trademarked term "990-style") are essentially the same design as the centre-pull caliper brake. The difference is that the two arm pivots attach directly to the frame or fork while those of the centre-pull caliper brake attach to an integral bridge frame that mounts to the frame or fork by a single bolt. Like roller cam brakes, this is a caliper design with pivots located above the rim. Thus U-brakes are often interchangeable with, and have the same maintenance issues as, roller cam brakes.

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V-BRAKESLinear-pull brakes or direct-pull brakes, commonly referred to by Shimano's trademark V-brakes, are a side-pull version of cantilever brakes and mount on the same frame bosses. However, the arms are longer, with the cable housing attached to one arm and the cable to the other. As the cable pulls against the housing the arms are drawn together. Because the housing enters from vertically above one arm yet force must be transmitted laterally between arms, the flexible housing is extended by a rigid tube with a 90° bend known as the "noodle". The noodle seats in a stirrup attached to the arm. A flexible bellows often covers the exposed cable

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MINI V-BRAKESThe mini V-brakes (also referred to as "mini V's") are V-brakes with shorter arms, typically between 8 and 9 centimeters. This reduces the required cable pull, making them compatible with brake levers intended for cantilever brakes.

Mini V-brakes retain advantages specific to V-brakes such as not requiring extra cable stops.

On the downside, their shorter arms provide very small tyre and wheel clearance and generally make for a less forgiving setup: they can only accommodate smaller tyre sizes compared to cantilever brakes, may pose problems for mounting fenders, can be clogged more easily by mud, and they can make it harder to change wheels out.

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ROLLER CAM BRAKES

Roller cam brakes are centre-pull cantilever brakes actuated by the cable pulling a single two-sided sliding cam. (First and second-class lever designs exist; first-class is most common and is described here.) Each arm has a cam follower. As the cam presses against the follower it forces the arms apart. As the top of each arm moves outward, the brake shoe below the pivot is forced inward against the rim. There is much in favor of the roller cam brake design. Since the cam controls the rate of closure, the clamping force can be made non-linear with the pull. And since the design can provide positive mechanical advantage,

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DELTA BRAKES

The delta brake is a road bicycle brake named due to its triangular shape. The cable enters at the centre, pulls a corner of a parallelogram linkage housed inside the brake across two opposite corners, pushing out at the other two corners on to the brake arms above the pivots, so that the arms below the pivots push pads in against the rim. A feature of the design is that the mechanical advantage varies as a tangent function across its range, where that of most other designs remains fixed.

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